gears.object: Add a new "property fallback" object type

This commit is contained in:
Emmanuel Lepage Vallee 2016-03-13 03:42:57 -04:00
parent e8c7e573cb
commit a77e650c5f
2 changed files with 105 additions and 1 deletions

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@ -9,8 +9,9 @@ local setmetatable = setmetatable
local pairs = pairs
local type = type
local error = error
local properties = require("gears.object.properties")
local object = { mt = {} }
local object = { properties = properties, mt = {} }
--- Verify that obj is indeed a valid object as returned by new()
local function check(obj)

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@ -0,0 +1,103 @@
---------------------------------------------------------------------------
--- An helper module to map userdata __index and __newindex entries to
-- lua classes.
--
-- @author Emmanuel Lepage-Vallee <elv1313@gmail.com>
-- @copyright 2016 Emmanuel Lepage-Vallee
-- @release @AWESOME_VERSION@
-- @module gears.object.properties
---------------------------------------------------------------------------
local object = {}
local properties = setmetatable({}, { __mode = 'k' })
local function cobj_register(cobj)
local fallback = {}
function fallback:rawset(_, prop, val)
fallback[prop] = val
end
function fallback:rawget(_, prop)
return fallback[prop]
end
properties[cobj] = fallback
return fallback
end
--- Add the missing properties handler to a CAPI object such as client/tag/screen
-- Valid args:
--
-- * **getter**: A smart getter (handle property getter itself)
-- * **getter_fallback**: A dumb getter method (don't handle individual property getter)
-- * **getter_class**: A module with individual property getter/setter
-- * **getter_prefix**: A special getter prefix (like "get" or "get_" (default))
-- * **setter**: A smart setter (handle property setter itself)
-- * **setter_fallback**: A dumb setter method (don't handle individual property setter)
-- * **setter_class**: A module with individual property getter/setter
-- * **setter_prefix**: A special setter prefix (like "set" or "set_" (default))
-- * **auto_emit**: Emit "property::___" automatically (default: false). This is
-- ignored when setter_fallback is set or a setter is found
--
-- @param class A standard luaobject derived object
-- @tparam[opt={}] table args A set of accessors configuration parameters
function object.capi_index_fallback(class, args)
args = args or {}
local getter_prefix = args.getter_prefix or "get_"
local setter_prefix = args.setter_prefix or "set_"
local getter = args.getter or function(cobj, prop)
-- Look for a getter method
if args.getter_class and args.getter_class[getter_prefix..prop] then
return args.getter_class[getter_prefix..prop](cobj)
end
-- Make sure something like c:a_mutator() works
if args.getter_class and args.getter_class[prop] then
return args.getter_class[prop]
end
-- In case there is already a "dumb" getter like `awful.tag.getproperty'
if args.getter_fallback then
return args.getter_fallback(cobj, prop)
end
local fallback = properties[cobj] or cobj_register(cobj)
-- Use the fallback property table
return fallback[prop]
end
local setter = args.setter or function(cobj, prop, value)
-- Look for a setter method
if args.setter_class and args.setter_class[setter_prefix..prop] then
return args.setter_class[setter_prefix..prop](cobj, value)
end
-- In case there is already a "dumb" setter like `awful.client.property.set'
if args.setter_fallback then
return args.setter_fallback(cobj, prop, value)
end
local fallback = properties[cobj] or cobj_register(cobj)
-- Use the fallback property table
fallback[prop] = value
-- Emit the signal
if args.auto_emit then
cobj:emit_signal("property::"..prop, value)
end
end
-- Attach the accessor methods
class.set_index_miss_handler(getter)
class.set_newindex_miss_handler(setter)
end
return setmetatable( object, {__call = function(_,...) object.capi_index_fallback(...) end})
-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80